.bit-log {
    flex-basis: 6vw;
    height: 9vw;
    background: url(../img/logo.png) no-repeat center center;
    background-size: 8vw 11.11vw;
}

.img-circle {
    width: 2vw;
    height: 2vw;
}

@media only screen and (max-width: 500px) {
    .img-circle {
        width: 4vw;
        height: 4vw;
    }
}

.img-search {
    height: 1.56vw;
    width: 2.19vw;
}

.img-search:hover {
    cursor: pointer;
}

@media only screen and (max-width: 500px) {
    .img-search {
        width: 4vw;
        height: 4vw;
    }
}

.picture1,
.picture2,
.picture4 {
    display: none;
    margin-top: 10vh;
    margin-left: 5vw;
    position: absolute;
    width: 20vw;
    height: 20vw;
}

.picture3 {
    margin-top: 10vh;
    margin-left: 5vw;
    position: absolute;
    width: 20vw;
    height: 20vw;
}

@media only screen and (max-width:700px) {
    .picture1,
    .picture2,
    .picture4 {
        margin-top: 18vh;
        margin-left: 7vw;
    }

    .picture3 {
        margin-top: 18vh;
        margin-left: 7vw;
    }
}